Recovery op molybdenum and similar



Patented May 30, 1933 UN T D {S A ES PAUL nnnoLn AND eusrnv A. KRAJEWSKI, or LEUNA: Gmmmi ssm s TO I; G. i rannnmnnnsrnrn axrrnnsnsnrnscnar'r, on FRANKFORT-ON-THE-MAIN, can,

MANY:.

RECOVERY or MOLYBDENUM Ami SIMILAR. METALS I No Drawing: Application filed A il's, 1932, Serial naeoasea andineeri aa December 17, 1930.

The present invention is a continuation 'in part of application Ser. N0. 580,49l, filed December 11th, 1931, and relates to the recovery of molybdenum, tungsten and vana- "diumitrom ores andotherfcrude material containing same. y

In order to obtain molybdenum and tungsten from'materials containing these elements as sulphides, such'as ores or industrial residues, it has been proposed to heat the initial materials with chlorine or hydrogen chloride or gases containing the same with an addition of oxygen or gases containing the same, such as'air, to convert the said metals into volatile oxychlorides. This process proceeds rather slowly at-temperatures' below about We have now found that the said process may be carried out sufliciently rapidly on a technical scale even at temperatures below G. if the said materials containing molybdenum or tungsten as sulphides are reated with chlorine orhydrogen chloride or gases containing at least one of the same with an addition of oxygen or gases containing. the same in the presence of not completely volatilizable carbonaceous substances. The amount of oxygen present in the gas should as a rule be from 3 to 10 per cent, by volume. The temperatures to be employed range between 250 and 400 0., preferably between 330 and 350 C.

As carbonaceous substances suitable for i being admixed with the said sulphidic coment in the crude materials from the start,

such as is the case with many exhausted catalytic masses, as for example those from the destructive hydrogenation of coal. If this is not the case, carbonaceous substances, for example lignite coke, wood charcoal, carbonized products such as carbon from molassesor the-like,are added tothe initial materials before thechlorinatingtreatment.

The amount of additional substance added- Itis may be varied' within wide limits. preferableto'employ at least one fifth of the amount of the metalliferous material tobe Worked up. r 5

The same method may-also be used-for working. up masses' containing vanadium in the formof its sulphides. In-this case' the chlorination proceeds quicklvand completely at temperatures of about 300C. 7 1

The not completely volatilizable carbonaceous'substances to be employed according tothe present invention appear to exert a catalyzing action onthe formation of chlorides without being converted themselves in the reaction. It seems improbable that under the conditions of working the said: carbo-.

naceous substances exert a reducing action since :tr'ee oxygen is additionally supplied. But we wish to be understood that we donot restrict ourselves-to this theory.

The valuable metals may be volatilized so that only a fraction of one percent remains in the residue andmay be recovered in a simple manner. The process is advantageously carried out on the counter current desired'after removal of gaseous by-products such as sulphur-dioxide, sulphur chloride,

'sulphuryl or thionylchloride orthe like by washing or adsorption.

Theffur'ther Working-up of the resulting volatile metal compounds is preferably effected by decomposition of"the..-readily decomposable'chlorine' compounds .with water or steam, the metal oxides or acids thus.

formed being finished .ofi in any desired manner.

The advantages of working at the said very principle and while re employing the'unexhausted reaction gases in circulation,,iif

low temperatures'are considerable. For ex ample the process alsoallows of the employment of crude materials which contain other metals which form volatile chlorides, suchas iron, aluminium and zinc, as wellas the said metals. The valuable chlorine compounds tov be recovered are scarcely conta1 n. inatedbythe chlorides of these other metals I slowly under the mild working conditions.

Furthermore there is theadvantage of economy in the heating material when selecting the constructional material for the reaction chamber because this has nounusual' requirements to fulfill as regards stability to heat. Certain nickel alloys, especially nickel copper alloys, such'as Monel metal,-

and special steels containing nickel and chromium, as for example VQA steel, are especial-' 1y advantageous as. the constructional 'material.- These materials are distinguished by great chemical resistance and undergo no appreciable attack, for example in the form of stirring arms and promoting means, even when used for several months and in spite of the great reactivity of the gases. They are therefore substantially superior for example to cast; iron and cast silicon,-materials which generally. speaking have good resistance to chemical attack. n v

The following examples will further illustratethe nature of this invention, but the invention is not restricted to theseexamples.

V H i Ewamplel.

- A catalyst used in the destructive hydrogenation of carbonaceous materials, such as tar, andconsistingsubstantially of the sulphides of zinc, molybdenum and magnesium contaminated by large amounts of asphaltio andresinous substances is first subjected to low temperature carbonization. It then con- :tains about 20 per cent of carbonized subchlorine gas to which 3 per cent of oxygen has .been added in counter current. The

set our hands. stances. The mass is'then led through a ro- I tary tubular furnace, at 320 C. while passing r duced in large amounts at the other end of the furnace in counter current to the charge. The vanadium is almost entirely taken u by the excess of chlorine gas in the form 0 the volatile chlorine compound and is isolated as described in Example 1.

With the same success awaste catalyst consisting substantially of compounds of tungsten with sulphur may be worked up.

What we claim is 1. In the working up of a crude material containing a sulphide of a metal of the group consisting of molybdenum, tungsten and vanadium, the step of treating said material "at a temperature between 250 and 400 C.

2. In the'process as claimed in claim. 1

working up a material containing a sulphide of molybdenum.

'3. In the process as claimed in claim 1 working up a material containing a sulphide of tungsten.

' l. 'In theprocess as claimed in claim working up a material containing a sulphide of vanadium.

lathe working up of a crude material containing a sulphide of a metal selected from the group consisting of molybdenum,

tungsten and Vanadium, the step of treating said sulphide at a temperature between 250 .and 400- C. and in the presence of a not completely volatilizable carbonaceous substance witha gas containing free oxygen and chlorine.

i .In testimony. whereof. .we have hereunto PAUL' HEROLD. GUSTAV A. KRAJEWSKI.

molybdenum evaporates in the form of its a .oxychloride; this is carried along by the hot v stream of chlorine into ;a;.cooled chamber wherein it separates' asa loose powder. The gases are led back again to the rotary furnace after washing with water. 1 The solidresidue only contains 0.8 per cent-of molybdenum.

- =3 Also a:chlorinega's'having a greater con- Q: tent in oxygenmay be used; thus'in the afore- I said treatment agas containing 10 per cent --equal parts of chlorine'gas andair intro- 

